1. Grandeurs et Unités - Mécanismes biologiques de l’action des rayonnements ionisants

2. Effets aigus d ’une irradiation accidentelle3. Cancers radio-induits4. Effets héréditaires radio-induits5. Effets de l ’irradiation in utero6. Législation: les normes de bases; principes de radioprotection

opérationnelle7. Travaux pratiques: emploi de détecteurs en situation de routine;

dosimétrie des travailleurs; visites des installations du contrôle physique

Prof. V. GrégoireDr. P. SmeestersProf. A. Wambersie, Mr J. Caussin

3

• Radiobiology for the Radiologist, Eric J. Hall. J.B. Lippincott Company, Philadelphia, 1994.

• 1990 recommendations of the International Commission on Radiological Protection, Annals of the ICRP, publication 60, 1991.

• Exposure to ionizing radiations: radiobiological effects and pathogenesis, A. Wambersie et al., Revue Médicale de Bruxelles, 17: 27-38 et 75-84, 1996 ou Louvain Med., 114: S97-S132, 1995.

• http://www.md.ucl.ac.be/IMRE/RPR2001.htm

4

5

• Chronology- acute effects- late effects

• Targeted population- somatic effects (irradiated person)- genetic effects (offspring)

• Characteristics- deterministic effects- stochastic effects

6

•  Japanese survivors of Hiroshima and Nagasaki

• Accidental irradiation (e.g. nuclear power station, industrial radiography, crystallography)

• Total body irradiation before bone marrow transplantation

7

• Deterministic effects- threshold- severity increases with dose- involve all irradiated individuals

• Somatic effect

• Dependent on- total dose- dose rate / fractionation- irradiated volume- ionizing radiation

8

• Prodromal syndrome

• Cerebrovascular syndrome

• Gastrointestinal syndrome

• Hematopoietic syndrome

• Skin reactions

9

Neuromuscular Gastrointestinal

≈ LD50 Easy fatigability AnorexiaNausea/vomiting

>> LD50 Fever Immediate diarrheaHypotension

• Onset: 5-15 min.• Peak: ≈ 30 min.• Duration: days

10

• Dose ≥ 100 Gy• Onset minutes• Σ nausea / vomiting

disorientationrespiratory distressdiarrheaseizurescomadeath in 48-72h

• R/ Ø

11

12

Sections of unirradiated mouse gut

13

• Dose ≥ 6 Gy• Onset few hours• Σ nausea / vomiting

diarrheadehydrationinfectiondeath within 10 days

• R/ fluids, electrolytes, proteins, ...anti-vomiting drugstransfusionantibiotics…

14

Sections of irradiated (10 Gy) mouse gut

15

16

• Dose 3 - 8 Gy• Onset 28 days• Σ skin petechia, bleeding

infectionanemiadeath within 30-60 days

• R/ pathogen-free environmentsupportive care: ATB, …bone marrow transplantation

17

Species LD50 (Gy)Sheep 1.55Pig 1.95Goat 2.30Guinea-pig 2.55Dog 2.65Monkey 3.5 - 5Human 4.5 - 5Rabbit 8.40Mouse 9.00Rat 9.00

18

19

20

• Dose > 4.5 Gy• Onset few hours - few weeks• Σ early erythema

dry desquamation (>10 Gy)moist desquamation (> 12-15 Gy)transient alopecia (> 5-10 Gy)permanent alopecia (> 10-15 Gy)

• R/ diffuse: supportive care (fluids, electrolytes, proteins, …)local: topical treatment

21

22

23

Clinical symptoms Time Estimated dose (TBI)Neurological / shock minutes > 10 Gy

Vomiting 0.5h > 10 Gy

Nausea, vomiting, asthenia >1h 6-10 Gy>2h 3-6 Gy>3h 1-2 Gy

Skin erythema first hours > 4.5 Gy (γ-irradiation)

24

Dose Lymphocytes count

< 1 Gy slight decrease (not more than 50% of normal value)

1 - 2 Gy ≈ 50% decrease in 24 - 48h

> 2 Gy dramatic decrease (<< 50%) within 24h